Communication apparatus, electronic mail transmitting method, and electronic mail transmitting program

ABSTRACT

A communication apparatus which is capable of enhancing security in transmitting an electronic mail to a destination mail address, using a transmission protocol, without degrading operability. A MFP  100  is connected to an authentication server  102  and a mail server  120  via a network, for transmitting an E-mail via the mail server according to SMTP. A user name and a password are entered in a user name entry screen. The MFP  100  requests the authentication server  102  to authenticate the entered user name and password. When the user name and the password are authenticated, the MFP  100  is operable to acquire an E-mail address  232 , a SMTP authentication user name  233 , and a SMTP authentication password  234  according to SMTP associated with the authenticated user name and password from the authentication server  102 . The MFP  100  requests the mail server  103  to authenticate the acquired SMTP authentication user name  233  and SMTP authentication password  234  according to SMTP. When the SMTP authentication user name  233  and the SMTP authentication password  234  are authenticated, the MFP is operable to transmit an E-mail to the mail server  103  according to SMTP.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a communication apparatus, anelectronic mail transmitting method, and an electronic mail transmittingprogram, which transmit electronic mails according to a predeterminedtransmission protocol.

2. Description of the Related Art

In recent years, with proliferation of computers and networking ofinformation, electronic mail communication for exchanging characterinformation via a network has been prevailing. Electronic mail cantransmit not only the body of an electronic mail message as characterinformation but also files in various formats as an attachment thereto.For example, Internet FAX, which transmits and receives image data as anattached file in the TIFF (Tag Image File Format) format has come intoproliferation.

Internet FAX (hereinafter referred to “iFAX”) is a communicationtechnique used for communication between a transmitting apparatus and areceiving apparatus, in which the transmitting apparatus converts imagedata read using a scanner into the TIFF format and transmits the TIFFimage data to the receiving apparatus, and the receiving apparatusprints out the received TIFF image data. To secure compatibility betweena plurality of apparatuses, the specification of TIFF image data forcommunication is standardized in details in the technical specificationRFC (Request for Comments) 2301 by the IETF (Internet Engineering TaskForce) which is an organization for standardizing Internet techniques.

Further, a SMTP authentication technique in which when transmitting anelectronic mail to the mail address of a transmission destinationaccording to Simple Mail Transfer Protocol (SMTP), user authenticationis carried out by a mail server before transmission, so as to preventillegal replaying of an electronic mail with a false mail address, isstandardized in the technical specification RFC 2554. An example of suchconventional technique of transmitting an electronic mail afterexecution of user authentication is described e.g. in Japanese Laid-OpenPatent Publication (Kokai) No. H11-234496.

Furthermore, the assignee of the present application has alreadyproposed a method in which when a user logs in to an authenticationserver in advance before transmitting an electronic mail, to havehis/her user name and password authenticated, he/she acquires anelectronic mail address associated with the authenticated user name, andthen transmits the electronic mail to the mail address of a transmissiondestination, using the acquired mail address as the address of thetransmission source (Japanese Patent Application No. 2003-066857).

However, even the proposed electronic mail transmitting method remainsto be improved in the following points.

When an electronic mail is transmitted using the SMTP authentication, ifset values (i.e. a user name and a password) specific to an apparatus(e.g. a communication apparatus, such as a MFP (Multi-FunctionPeripheral)) are used as the user name and password for SMTPauthentication, a log of the user name of a user who logged in to theauthentication server can be stored as a transmission log in theapparatus. However, only the user name specific to the apparatus isstored in the mail server. As a result, the log stored in the apparatusis different from the log stored in the mail server, which makes itdifficult to correlate these logs with each other, and hence to identifythe real sender. Further, there still remains the possibility that aperson other than the user, who knows the user name and passwordspecific to the apparatus, might perform a transmitting operation usingthe mail address as a disguised user.

Although this inconvenience can be avoided by inputting the user nameand password used for SMTP authentication without using the user nameand password specific to the apparatus each time an E-mail istransmitted using SMTP authentication, this leads to degradation ofoperability.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a communicationapparatus, an electronic mail transmitting method, and an electronicmail transmitting program, which are capable of enhancing security intransmission of an electronic mail to a destination mail address, usinga transmission protocol, without degrading operability.

To attain the above object, in a first aspect of the present invention,there is provided a communication apparatus connected to anauthentication apparatus and a mail distributing apparatus via anetwork, for transmitting an electronic mail via the mail distributingapparatus according to a predetermined transmission protocol, comprisingan input device via which user information is input, a userauthentication requesting device that requests the authenticationapparatus to authenticate the input user information, an authenticationinformation acquisition device that is operable when the userinformation is authenticated, to acquire information for authenticationaccording to the transmission protocol associated with the authenticateduser information from the authentication apparatus, a transmissionauthentication requesting device that requests the mail distributingapparatus to authenticate the acquired information for authentication,according to the transmission protocol, and a transmission device thatis operable when the acquired information for authentication isauthenticated, to transmit an electronic mail to the mail distributingapparatus according to the transmission protocol.

With the arrangement of the first aspect of the present invention,authentication of the input user information is requested of theauthentication apparatus, and when the user information isauthenticated, information for authentication according to thetransmission protocol associated with the authenticated user informationis acquired from the authentication apparatus. Then, authentication ofthe acquired information for authentication is requested of the maildistributing apparatus according to the transmission protocol, and whenthe acquired information for authentication is authenticated, anelectronic mail is transmitted to the mail distributing apparatusaccording to the transmission protocol. This makes it possible toenhance security in transmission of an electronic mail to a destinationmail address, using the transmission protocol, without degradingoperability.

Preferably, the authentication apparatus comprises a storage device thatstores an electronic mail address associated with the user informationand the information for authentication according to the transmissionprotocol associated with the user information, and the authenticationinformation acquisition device acquires the electronic mail address andthe information for authentication stored in the storage device.

With this arrangement of the preferred embodiment, when the userinformation is authenticated, an electronic mail address associated withthe authenticated user information is acquired from the authenticationapparatus. This makes it possible to prevent relaying of maliciouselectronic mails e.g. using false electronic mail addresses.

Preferably, the information for authentication comprises a user name anda password for SMTP authentication, the user name and the password beingassociated with the user information.

To attain the above object, in a second aspect of the present invention,there is provided a communication apparatus connected to a maildistributing apparatus via a network, for transmitting an electronicmail via the mail distributing apparatus according to a predeterminedtransmission protocol, comprising an authentication information storagedevice that stores information for authentication according to thetransmission protocol, an input device via which user information isinput, a user authentication requesting device that requestsauthentication of the input user information, an authenticationinformation acquisition device that is operable when the userinformation is authenticated, to acquire information for authenticationaccording to the transmission protocol associated with the authenticateduser information from the authentication information storage device, atransmission authentication requesting device that requests the maildistributing apparatus to authenticate the acquired information forauthentication, according to the transmission protocol, and atransmission device that is operable when the acquired information forauthentication is authenticated, to transmit an electronic mail to themail distributing apparatus according to the transmission protocol.

With the arrangement of the second aspect of the present invention, itis possible to obtain the same advantageous effects as provided by thefirst aspect of the present invention.

Preferably, the authentication information storage device stores anelectronic mail address associated with the user information and theinformation for authentication according to the transmission protocolassociated with the user information, and the authentication informationacquisition device acquires the electronic mail address and theauthentication information stored in the authentication informationstorage device.

With this arrangement of the preferred embodiment, it is possible toobtain the same advantageous effects as provided by the first-mentionedpreferred embodiment of the first aspect of the present invention.

Preferably, the information for authentication comprises a user name anda password for SMTP authentication, the user name and the password beingassociated with the user information.

To attain the above object, in a third aspect of the present invention,there is provided an electronic mail transmitting method executed by acommunication apparatus connected to an authentication apparatus and amail distributing apparatus via a network, for transmitting anelectronic mail via the mail distributing apparatus according to apredetermined transmission protocol, comprising an input step ofinputting user information, a user authentication requesting step ofrequesting the authentication apparatus to authenticate the input userinformation, an authentication information acquisition step of acquiringinformation for authentication according to the transmission protocolassociated with the authenticated user information from theauthentication apparatus, when the user information is authenticated, atransmission authentication requesting step of requesting the maildistributing apparatus to authenticate the acquired information forauthentication, according to the transmission protocol, and atransmission step of transmitting an electronic mail to the maildistributing apparatus according to the transmission protocol, when theacquired information for authentication is authenticated.

To attain the above object, in a fourth aspect of the present invention,there is provided an electronic mail transmitting method executed by acommunication apparatus connected to a mail distributing apparatus via anetwork, for transmitting an electronic mail via the mail distributingapparatus according to a predetermined transmission protocol, comprisingan input step of inputting user information, a user authenticationrequesting step of requesting authentication of the input userinformation, a retaining step of retaining information forauthentication according to the transmission protocol on a user-by-userbasis, an authentication information acquisition step of acquiringinformation for authentication according to the transmission protocolassociated with the authenticated user information, from theauthentication information retained in the retaining step, atransmission authentication requesting step of requesting the maildistributing apparatus to authenticate the acquired information forauthentication, according to the transmission protocol, and atransmission step of transmitting an electronic mail to the maildistributing apparatus according to the transmission protocol, when theinformation for authentication is authenticated.

To attain the above object, in a fifth aspect of the present invention,there is provided an electronic mail transmitting program executed by acommunication apparatus connected to an authentication apparatus and amail distributing apparatus via a network, for transmitting anelectronic mail via the mail distributing apparatus according to apredetermined transmission protocol, comprising an input module forinputting user information, a user authentication requesting module forrequesting the authentication apparatus to authenticate the input userinformation, an authentication information acquisition module foracquiring information for authentication according to the transmissionprotocol associated with the authenticated user information from theauthentication apparatus, when the user information is authenticated, atransmission authentication requesting module for requesting the maildistributing apparatus to authenticate the acquired information forauthentication, according to the transmission protocol, and atransmission module for transmitting an electronic mail to the maildistributing apparatus according to the transmission protocol, when theacquired information for authentication is authenticated.

To attain the above object, in a sixth aspect of the present invention,there is provided an electronic mail transmitting program executed by acommunication apparatus connected to a mail distributing apparatus via anetwork, for transmitting an electronic mail via the mail distributingapparatus according to a predetermined transmission protocol, comprisingan input module for inputting user information, a user authenticationrequesting module for requesting authentication of the input userinformation, a retaining module for retaining information forauthentication according to the transmission protocol on a user-by-userbasis, an authentication information acquisition module for acquiringinformation for authentication according to the transmission protocolassociated with the authenticated user information, from theauthentication information retained by the retaining module, atransmission authentication requesting module for requesting the maildistributing apparatus to authenticate the acquired information forauthentication, according to the transmission protocol, and atransmission module for transmitting an electronic mail to the maildistributing apparatus according to the transmission protocol, when theinformation for authentication is authenticated.

The above and other objects, features, and advantages of the inventionwill become more apparent from the following detailed description takenin conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram showing the overall arrangement of an electronicmail system including a communication apparatus according to a firstembodiment of the present invention;

FIG. 2 is a block diagram showing the configuration of a MFP(Multi-Function Peripheral) appearing in FIG. 1;

FIG. 3 is a diagram showing the layered structure of network protocolspossessed by the MFP;

FIG. 4 is a diagram showing an operating screen displayed duringexecution of a program for looking up user information registered in anauthentication server appearing in FIG. 1 and/or editing contents of theuser information;

FIG. 5 is a flowchart of a log-in process executed by the MFP foracquiring an E-mail address, a SMTP authentication user name, and a SMTPauthentication password;

FIG. 6 is a diagram useful in explaining details of the procedure ofprocessing carried out between the MFP and the authentication server,for user authentication;

FIG. 7 is a diagram showing a transmission setup screen displayed on anoperating section;

FIG. 8 is a diagram showing an address book for managing transmissiondestination information;

FIG. 9 is a flowchart of a transmission process for reading an originalby a scanner and then transmitting an E-mail to destinations;

FIG. 10 is a diagram useful for explaining details of the procedure ofSMTP authentication performed between the MFP and a mail server,executed in a step S17 in FIG. 9;

FIG. 11 is a diagram showing an operating screen displayed duringexecution of a program for looking up user information registered in theauthentication server and/or editing contents of the user information,according to a second embodiment of the present invention;

FIG. 12 is a flowchart of a log-in process executed by the MFP foracquiring an E-mail address, a SMTP authentication user name, and a SMTPauthentication user password; and

FIG. 13 is a diagram showing a transmission setup screen displayed on anoperating section.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention will now be described in detail with reference tothe drawings showing preferred embodiments thereof. In the drawings,elements and parts which are identical throughout the views aredesignated by identical reference numerals, and duplicate descriptionthereof is omitted.

FIG. 1 is a diagram showing the overall arrangement of an E-mail systemincluding a communication apparatus according to a first embodiment ofthe present invention. The E-mail system is comprised of a plurality ofapparatuses and devices connected to a first network 105 and a secondnetwork 125 via the Internet 110 as a worldwide network.

The first network 105 is assigned a domain name “xyz.co.jp”, and hasconnected thereto MFPs (Multi Function Peripherals) 100 and 101, anauthentication server 102, a Mail/POP server 103, and a client PC 104. Asecond network 125 is assigned a domain name “abc.co.jp”, and hasconnected thereto a Mail and POP server 120, a PC 121, and an InternetFAX 122.

The MFPs 100 and 101 are equipped with a scanner and a printer, and havea copying function, a facsimile (FAX) transmitting and receivingfunction, and a printer function for printing data generated by acomputer. Further, the MFP 100 is assigned a host name “copy1.xyz.co.jp”and an E-mail address “ifax@copy1.xyz.co.jp”. The MFP 101 is assigned ahost name “copy2.xyz.co.jp” and an E-mail address“ifax@copy2.xyz.co.jp”.

The authentication server 102 performs user authentication for thedomain of the first network 105, and a plurality of pairs of user namesand passwords valid in the domain are registered in the authenticationserver 102. The PC 104 has general-purpose E-mail software installedtherein, and is assigned an E-mail address “syain1@xyz.co.jp”. When thepower of the client PC 104 is turned on, entry of the user name andpassword is requested. Then, when the user enters the user name andpassword, the client PC 104 inquires of the authentication server 102 asto whether or not the entered user name and the password match theregistered user name and password. If the user has the user name and thepassword registered in the authentication server 102, the use of the PC104 is permitted.

The Mail/POP server 103 has both the functions of a mail server (SMTPserver) and a POP server. Needless to say, the mail server (SMTP server)and the POP server may be implemented by respective separateapparatuses. The Mail/POP server 120 in the domain of the second network125 has the same functions as those of the Mail/POP server 103. Forexample, when an E-mail is transmitted from the PC 104 to an E-mailaddress “pcmail@abc.co.jp”, E-mail data generated by the PC 104 is sentto the mail server 103 using SMTP (Simple Mail Transfer Protocol), andthen further sent from the mail server 103 to the mail server 120 viathe Internet 110 using SMTP.

The PC 121 has general-purpose E-mail software installed therein. The PC121 monitors at predetermined time intervals whether or not any E-mailhas arrived at the POP server 120, using POP3 (Post OfficeProtocol-Version 3), and if any E-mail has arrived at the POP server120, the PC 121 receives the E-mail data. On the other hand, when the PC121 having the E-mail address “pcmail@abc.co.jp” sends an E-mail to thePC 104 having the E-mail address “syain1@xyz.co.jp”, the route isreversed, that is, E-mail data generated by the PC 121 is sent to themail server 103 by way of the mail server 120. Then, the PC 104 acquiresthe delivered E-mail data using the POP3 protocol. The PC 104 has thecapabilities of interpreting E-mail data in the MIME format or the like,and decoding image data contained in the E-mail data, for reproduction.

The MFPs 100 and 101 have two transmission modes: an E-mail transmissionmode for transmitting an image received using the facsimile (FAX) oriFAX receiving function, or a monochrome/color image scanned by thescanner, on the assumption that the same will be sent to a generalE-mail address, and an iFAX transmission mode for transmitting the imageon the assumption that the same will be sent to an apparatus compliantwith the iFAX standard. The MFPs 100 and 101 use SMTP and POP3 ascommunication protocols to perform operations similar to thetransmitting and receiving operations by the PCs described above.

In the E-mail transmission mode, an image in the JPEG file format(hereinafter simply referred to as a JPEG image) is transmitted. Forexample, when a color image is transmitted to the client PC 104 havingthe E-mail address “syain1@xyz.co.jp”, the PC 104 receives the E-mailand displays the JPEG image, using a general-purpose image viewer. Inthe iFAX transmission mode, an image in the TIFF format is transmittedaccording to the technical specification RFC 2301. For example, an imageis transmitted or received by the MFP 100 or the MFP 101 compliant withthe iFAX standard or the Internet FAX 122. Between apparatuses capableof processing color images, JPEG images in the TIFF format aretransmitted or received.

FIG. 2 is a block diagram showing the configuration of the MFP 100. TheMFP 100 and the MFP 101 are identical in configuration, and hence adescription will be given of only the configuration of the MFP 100. TheMFP 100 is comprised of a CPU 130, a ROM 131, a RAM 132, an operatingsection 133, a scanner 134, a printer 135, an image processing circuit136, a hard disk 137, a network interface (I/F) 138, a formatter section139, and a FAX section 140.

The CPU 130 functions as a control circuit that controls the overalloperation of the system. The CPU 130 executes programs stored in the ROM131 and uses the RAM 132 as a work area. The operating section 133 iscomprised of hardware keys, such as a start key and keys of a ten keypad, and a LCD display panel that displays buttons as software keys anddetects a touch of any of the displayed buttons by a user's finger, forsmooth execution of user operation.

The scanner 134 converts an original image into electric image data byphotoelectric conversion. The scanner 134 is comprised of a platen glasson which an original conveyed from an original feeder is placed, ascanner unit including a lamp for illuminating the original, a CCD imagesensor for receiving reflected light from the original, mirrors andlenses for guiding the reflected light from the original to the CCDimage sensor, and an A/D conversion circuit for converting an electricsignal subjected to photoelectrical conversion by the CCD image sensorinto digital data, none of the above-mentioned component elementsincluded in the scanner 134 being shown in FIG. 2. When an originalconveyed from the original feeder is placed on the platen glass, thelamp is turned on and the scanner unit is caused to start travelingwhereby the original is scanned while being exposed to light. Reflectedlight from the original is guided to the CCD image sensor via themirrors and the lens. The reflected light is converted into an electricsignal by the CDD image sensor, and then the electric signal isconverted into digital data by the A/D conversion circuit. Aftercompletion of the operation for reading the original, the original isdischarged from the platen glass.

The printer section 135 prints image data on a recording sheet. Theprinter section 135 is comprised of a laser emitting section, aphotosensitive drum, a transfer section, a fixing section, a dischargeroller, and a sorter having a plurality of bins. The laser emittingsection generates a laser beam dependent on the image data. When thelaser beam is irradiated onto the photosensitive drum, a latent image isformed on the photosensitive drum according to the laser beam. Developeris applied to the latent image on the photosensitive drum by adeveloping device, and a recording sheet is fed from a sheet feedcassette in timing synchronous with the start of laser radiation by thelaser emitting section, and conveyed to the transfer section. Thedeveloper attached to the photosensitive drum as a developer image istransferred onto the recording sheet. When the recording sheet with thedeveloper image transferred thereon is conveyed to the fixing section,the fixing section fixes the developer image on the recording sheet byheating and pressing the recording sheet. The recording sheet havingpassed through the fixing section is discharged by the discharge roller.Discharged recording sheets are sorted by the sorter into bins thereof.

The image processing circuit 136 is comprised of a large-capacity imagememory, an image rotating circuit, a resolution change and scalingcircuit, and an encoding and decoding circuit for encoding and decodingMH, MR, MMR, JBIG, JPEG, and like formats of data, and carries outvarious image processing including shading, trimming, and masking. Thehard disk 137 is a large-capacity recording medium connectable by aninterface (I/F), such as a SCSI interface or a USB interface. Therecording medium is not limited to a hard disk, but a magneto-opticaldisk (MO) or the like may be employed.

The network I/F 138 is implemented by an Ethernet (registered trademarkof Xerox Corporation, US) typified by 10 BASE-T and 100 BASE-T, or aToken Ring (registered trademark of IBM Corporation, US), and operatesto achieve a network data link for connection to the network. Theformatter section 139 includes an IEEE 1284-compliant parallel interfaceand a PC interface (I/F), such as USB, and generates image data based onPDL (Page Description Language) data received from a personal computervia the PC interface (I/F) or a network I/F 138. The image processingcircuit 136 performs image processing, such as rendering, on thegenerated image data to print the same by the printer 135.

The FAX section 140, which is connected to a telephone line, is afacsimile I/F circuit including a NCU (Network Control Unit), a MODEM(Modulator/Demodulator), and so on. The FAX section 140 causes the imageprocessing circuit 136 to perform image processing on image data read bythe scanner 134, and then transmits the processed image data to anotherfacsimile (FAX) machine via the telephone line, or receives image datasent from another facsimile (FAX) machine and then causes the imageprocessing circuit 136 to perform image processing on the image data forprinting by the printer 135.

The scanner 134, the printer 135, the image processing circuit 136, theformatter section 139, and the FAX section 140 are interconnected via ahigh-speed video bus 142 separate from a CPU bus 141 connected to theCPU 130, so that image data can be transferred at high speed. The use ofthe high-speed video bus 142 enables the image processing circuit 136 toperform image processing on the image data read by the scanner 134, andthe printer 135 to print the processed image data to thereby realize acopying function.

Further, the MFP 100 has a transmission (Send) function for transmittingimage data read by the scanner 134 and processed by the image processingcircuit 136 to the network 105 via the network I/F, and an iFAX functionfor transmitting image data generated by the image processing circuit136 according to the technical specification RFC 2301, using an E-mailprotocol.

FIG. 3 is a block diagram showing the layered structure of networkprotocols possessed by the MFP 100. The network protocols can be roughlygrouped into three layers: an IP (Internet Protocol) layer 200, a TCP(Transmission Control Protocol)/UDP (User Datagram Protocol) layer 201,and an application layer 202.

The IP layer 200 is an Internet protocol layer that provides a servicefor delivering a message from a source host to a destination host viarelay nodes, such as routers. The IP layer 200 performs a routingfunction for managing source addresses from which data is transmittedand destination addresses to which data is transmitted, and determininga route in the network through which data is sent to the destinationhost, based on address information.

The TCP/UDP layer 201 is a transport layer that provides a service forpassing a message from a transmission application process to a receptionapplication process. The TCP, which is a connection-type serviceprotocol, ensures high reliability for communication, whereas the UDP,which is a connectionless-type service protocol, does not ensurereliability.

The application layer 202 defines a plurality of protocols. Theprotocols defined by this layer 202 include FTP (File Transfer Protocol)as a protocol for file transfer services, SNMP (Network ManagementProtocol) as a protocol for network management, LPD as a server protocolfor printing by the printer, HTTPd as a protocol for WWW (World WideWeb) servers, SMTP (Simple Mail Transfer Protocol) as a protocol forE-mail transmission and reception, and POP3 (Post OfficeProtocol-Version 3) as a protocol for E-mail downloading. Further, theapplication layer 202 also contains a Kerberos authentication programdefined by the technical specification RFC 1510.

FIG. 4 is a diagram showing an operating screen displayed duringexecution of a program for looking up user information registered in theauthentication server 102 and/or editing contents of the userinformation. The user information is comprised of a user name 230, apassword 231, an E-mail address 232, a SMTP authentication user name233, and a SMTP authentication password 234. The user name 230 is thename of a user who is permitted to use a computer within the domain(principal) assigned the domain name “xyz.co.jp”, which is managed bythe authentication server 102. In FIG. 4, there are registered usernames “syain1” to “syain5”. In the columns of the password 231, thereare registered passwords associated with the respective user names.Here, each password is displayed as “xxxxx” so as to prevent a thirdparty from viewing the password easily.

In the columns of the E-mail address 232, there are registered E-mailaddresses usable by the respective users registered in theauthentication server 102. The E-mail address associated with the username “syain1” is “syain1@xyz.co.jp”. The E-mail address associated withthe user name “syain2” is “syain2@xyz.co.jp”. The E-mail addressassociated with the user name “syain3” is “syain3@xyz.co.jp”. The E-mailaddress associated with the user name “syain4” is “syain4@xyz.co.jp”.The E-mail address associated with the user name “syain5” is“syain5@xyz.co.jp”.

The SMTP authentication user name 233 and the SMTP authenticationpassword 234 are user names and passwords to be used for SMTPauthentication (RFC 2554) which is executed according to the SMTPprotocol before transmission of an E-mail e.g. from the MFP 100, the MFP101 or the PC 104 to the mail server 103, to thereby preventunauthorized access or illegal relay of an E-mail with a false sendername (From Address). Although in FIG. 4, the SMTP authentication usernames associated with the user names “syain1” to “syain5” are identicalto the associated user names, it is to be understood that differentnames can be used. Further, similarly to the password 231, the SMTPauthentication password 234 is displayed as “xxxxx” so as to prevent athird party from viewing the same easily.

An add key 240 is used for registration of a new user. A delete key 241is used for deleting a registered user. A property key 242 is used formodifying registered contents, and when the property 242 is depressed,the registered contents are displayed.

FIG. 5 is a flowchart of a log-in process executed by the MFP 100, foracquiring an E-mail address, a SMTP authentication user name, and a SMTPauthentication password. By executing this log-in process, the MFP 100requests the authentication server 102 to perform user authentication,whereby E-mail can be used using a designated user name. This alsoapplies to the MFP 101, and therefore a description will be given of thelog-in process of the MFP 100 alone.

After the main power of the MFP 100 is turned on and initialization ofthe memory, I/O ports, etc. is executed, the present log-in process isstarted on condition that “User Authentication” is set to “Execute” bysystem user configuration. In this state, processing requiring useroperation, such as copying, is disabled, and a screen prompting the userto enter a user name is displayed on the operating section 133.

First, a user name entry screen is displayed, and entry of a user nameby the user is awaited (step S1) When the user name is entered, entry ofa password is awaited (step S2). When the password is entered, the username and the password are sent to the authentication server 102 forauthentication thereby (step S3).

Then, it is determined whether or not “authentication OK” has beenreturned from the authentication server 102, i.e. whether or not it isconfirmed by the authentication that the entered user name and passwordmatch the user name 230 and the password 231 registered in theauthentication server 102 (step S4). If an invalid user name and/or aninvalid password have/has been entered, i.e., if not “authentication OK”but “authentication NG” has been returned, the process returns to thestep S1, wherein the same processing as described above is carried outagain on the user name entry screen. On the other hand, if“authentication OK” has been returned, an E-mail address 232 of the userhaving logged in, which is registered in the authentication server 102,is acquired from the authentication server 102 (step S5). Further, theuser's SMTP authentication user name 233 and SMTP authenticationpassword 234 are acquired from the authentication server 102 (steps S6and S7), followed by terminating the present process.

When the user authentication is normally completed, the processingrequiring user operation, such as copying or transmission (SEND),becomes executable. Although in the present embodiment, the user nameand the password are entered for user authentication, a method usingbiometrics authentication based on a fingerprint, an iris pattern, orthe like, or a method using a contact-type or non-contact-type controlcard may be employed.

FIG. 6 is a diagram useful in explaining details of the procedure ofprocessing carried out between the MFP 100 and the authentication server102, for user authentication. The user authentication method of theauthentication server 102 is an authentication method using Kerberos asone of protocols of the application layer 202. This method isstandardized as the technical specification RFC 1510.

First, when a Kerberos authentication service request KEB_AS_REQ is sentfrom the MFP 100 as a client to the authentication server 102 (T1) tomake an inquiry as to whether or not the user is valid, an encryptedlog-on session key and client authentication data are returned as aKerberos authentication service reply KEB_AS_REP from the authenticationserver 102 to the MFP 100 (T2).

Based on the data, a Kerberos ticket authorization service requestKEB_TGS_REQ is generated, and the MFP 100 requests qualificationinformation from the authentication server 102 (T3). Encrypted clientauthentication data is returned as a Kerberos ticket authorizationservice reply KEB_TGS_REP from the authentication server 102 (T4).

Based on the data, a Kerberos application request KEB_AP_REQ isgenerated, and the MFP 100 asks the authentication server 102 to permituse of service (T5). Then, when the Kerberos application replyKEB_AP_REP is returned from the authentication server 102 (T6), if thereturned data is normal and it is shown that time data in the returneddata is within a predetermined time period, the MFP 100 determines thatthe authentication is successful.

Although in the present embodiment, the three requests are sent to thesame authentication server, this is not limitative, but a plurality ofservers may be used e.g. depending on the network configuration.Further, it is possible to employ another authentication method, such asDH (Diffie-Hellman) authentication.

FIG. 7 is a diagram showing a transmission setup screen displayed on theoperating section 133. The transmission setup screen is displayed on theoperating section 133 when image data read by the scanner 134 is to besent by E-mail after normal completion of log-in using the user name“syain1” in the log-in process shown in FIG. 5. In a field “Readingsize” 300, the size of an original to be read by the scanner 134 isdesignated. For originals to be read, any one of sheet sizes includingA3, A4, A5, B4, B5, 11*17, LTR, and STMT, and the orientation of thesheet can be designated. In FIG. 7, “auto” is currently set in the field“Reading size” 300, and hence a value detected by an original detectionsensor incorporated in the scanner 134 is read in.

In a field “Resolution” 301, a resolution in which an original is to beread by the scanner 134 can be designated. For the resolution, any oneof 200*100 dpi, 200*200 dpi, 200*400 dpi, 300*300 dpi, 400*400 dpi and600*600 dpi can be designated. In FIG. 7, a default value 200*200 dpi iscurrently set. Further, in a field “Details” 302, it is possible tospecify detailed operations for scanning, such as scanning density, thetype of the original, double-sided reading, duplex-to-duplex copy, andimage quality adjustment.

In a field “Subject” 304 is entered a title given to an E-mail to besent, and in a field “Body” 305 is entered the body of the E-mail. Wheneach of the setting fields is selected, a software keyboard is displayedto allow entry of a character string. A field “Address” 303 is providedfor specifying a destination address.

FIG. 8 is a diagram showing an address book for managing transmissiondestination information. The E-mail addresses of candidate transmissiondestinations are displayed in a column “Address” 352. When a checkmarkis placed in a checkbox of a column “Selection” 350 of each of selectedaddresses, whereby the selected address is entered in a field “To:” ofan E-mail before the E-mail is sent. In a column “MODE” 351, it ispossible to designate either the E-mail transmission mode fortransmitting an E-mail on the assumption that the same will be sent to ageneral E-mail address, or the iFAX transmission mode for transmittingan E-mail on the assumption that the same will be sent to an iFAXapparatus equipped with a function enabling transmission/reception ofInternet Faxes between apparatuses. In FIG. 8, there are designated twoE-mail destinations (E-mail addresses “pcmail@abc.co.jp” and“syain1@xyz.co.jp”) for the E-mail transmission mode, and one iFAXdestination (E-mail address “ifax@abc.co.jp”) for the iFAX transmissionmode.

FIG. 9 is a flowchart of a transmission process for reading an originalby the scanner 134 and then transmitting an E-mail to each of selecteddestinations. A program for executing the present process is stored in astorage medium (the ROM 131 or the hard disk 137) of the MFP 100, andcarried out by the CPU 130 when an E-mail is sent to the addresses.

First, it is determined whether or not the iFAX transmission mode isselected as the transmission mode (MODE 351) (step S11). If the iFAXtransmission mode is selected, the address of the apparatus, which isentered in a user mode, is set to a field “From” of the header sectionof the E-mail (step S12). Then, the E-mail address 232 associated withthe user name 230 set in the log-in process is set to a field “sender”of the E-mail (step S13; See FIG. 4). In this case, since the user haslogged in using the user name “syain1”, the E-mail address“syain1@xyz.co.jp” associated with the user name “syain1” is set to theaddress of the field “Sender” of the E-mail. After having set the “From”field and the “Sender” field, an image header, which has been generatedas image data, based on the information of the E-mail address of thetransmitting apparatus, the abbreviated name of the transmissiondestination, and a transmission time, is attached to the upper end ofthe image read by the scanner.

On the other hand, if the iFAX transmission mode is not selected as thetransmission mode, but the E-mail transmission mode is selected, theE-mail address 232 associated with the user name 230, which has been setin the log-in process, is set to the “From” field (step S15). In thiscase, the “Sender” field is not generated.

Then, a mail data generation process for generating a mail header,adding MIME information, encoding an attached file according to aBASE-64 encoding method, and so forth is carried out based on theinformation in the “From” field and the “Sender” field (step S16).

Before the generated E-mail data is sent to the mail server 103, SMTPauthentication is performed using the SMTP authentication user name andthe SMTP authentication password acquired from the authentication server102 in the steps S6 and S7, respectively (step S17), and the result ofthe SMTP authentication is determined (step S18). The SMTPauthentication will be described in detail hereinafter. After completionof the authentication, i.e. when “authentication OK” is returned, thedata is transmitted to the mail server 103, using SMTP (step S19). Whenthe transmission is completed, the user name 230 specified in the log-inprocess, the transmission destination information, a transmission date,the transmission time, the number of pages for transmission, and theresult of the transmission are written in a log (step S20), followed byterminating the present process. On the other hand, if the result of theauthentication is “authentication NG” in the step S18, the process isimmediately terminated without executing the transmission.

The data written in the log by the MFP 100 is printed as a transmissionresult report for notifying the result of the transmission or as acommunication management report which is generated whenever apredetermined number of transmission events are completed. The printedreport allows identification of senders of sent jobs. Further, since alog of the times of execution of SMTP authentication, the authenticationuser names, and so forth is stored in the mail server 103, the contentsof the transmission management report or the communication managementreport can be checked against the contents of the log stored in the mailserver 103. Thus, the validity of the log can be checked. The datawritten in the log can be displayed as a list on the operating section133.

FIG. 10 is a diagram useful for explaining details of the procedure ofthe SMTP authentication performed between the MFP 100 and the mailserver 103 in the step S17. This SMTP authentication makes it possibleto authenticate the sender of an E-mail before the E-mail is sent fromthe MFP 101 to the mail server 103, to thereby prevent relaying ofmalicious E-mails e.g. using false E-mail addresses. The SMTPauthentication process described below is mainly executed by the CPU ofthe MFP 100 and that of the mail server 103.

First, when the MFP 101 accesses the mail server 103 (T11) by SMTP, anumeral “220” indicating that the SMTP service is ready, and a domainname are returned from the mail server 103 (T12). When the MFP 101 as aclient sends an EHLO command indicative of the start of an extended SMTPsession to the mail server 103 (T13), a command response in the form ofa message starting with a numeral “250” indicating that the requestedcommand is successful is returned from the mail server 103 (T14).Further, responses based on one or more SMTP extended functions owned bythe mail server 103 are returned (T15 and T16). The T15 responseindicates that the mail server 103 has a DSN (Delivery StatusNotifications) service function, and the T16 response indicates that themail server 103 supports a SMTP authentication function SMTP AUTH, andsupports authentication methods CRAM-MD 5 and DIGEST-MD 5.

Since it is thus indicated that the mail server 103 is compatible withSMTP AUTH, the MFP 101 sends a command indicating that SMTP AUTH shouldbe used for authentication, and CRAM-MD 5 should be used as theauthentication method (T17). The mail server 103 returns a numeral “334”indicative of continuation of the request and a character string asserver challenge data (T18). The MFP 101 creates a cryptographicpassword encrypted by CRAM-MD 5 from the acquired server challenge dataand password, and returns the character strings of the encrypted username and password (T19).

Similarly, the mail server 103 also creates a cryptographic passwordfrom the server challenge data sent to the MFP 101 and the passwordassociated with the user name received from the MFP 101, and detects amatch between the created cryptographic password and the cryptographicpassword sent from the MFP 101 to thereby validate the password from theMFP 101. When the validity of the password is verified, the mail server103 sends a message starting with a numeral “235” indicative ofsuccessful authentication (T20), followed by terminating the SMTPauthentication.

Thereafter, the E-mail data is transmitted by the normal sequence ofSMTP, as described above. When the transmission is completed, the mailserver 103 records information of the E-mail address of the MFP 101 fromwhich the E-mail has been received, the E-mail address of thetransmission destination, the user name subjected to the SMTPauthentication, the transmission date and time, etc. in the log file.The administrator of the mail server 103 can refer to the recorded logfile.

As described above, according to the first embodiment, since datawritten in the log by the MFP 100 is printed as a transmission resultreport or a communication management report, the sender of thetransmitted job can be identified. On the other hand, the mail server103 stores a log of the times of execution of SMTP authentication theauthentication user names, and so forth. Therefore, an actual sender canbe identified by comparing the contents of the transmission resultreport or the communication management report with those of the log inthe mail server. Thus, security in transmission using SMTPauthentication can be enhanced without degrading operability.

Further, there is no need to set a SMTP user name, a SMTP authenticationpassword, and an E-mail address to a MFP, which facilitates managementincluding registration and modification of these data. Further, the logof user names authenticated by SMTP authentication is stored in the mailserver, as described above, so that it is possible to compare the logwith the transmission log stored in the MFP on a one-to-one basis, tothereby enhance security.

In the following, a description will be given of a second embodiment ofthe present invention with reference to FIGS. 11 to 13.

As distinct from the first embodiment in which SMTP authentication usernames and SMTP authentication passwords are managed by theauthentication server, in the present embodiment, they are managed bythe MFPs. That is, user names for SMTP authentication and passwordsassociated therewith, which are managed by the authentication server 102in the first embodiment are stored in the hard disk 137 in the secondembodiment.

An E-mail system including a communication apparatus according to thesecond embodiment is substantially identical in configuration to that ofthe first embodiment, and therefore component parts identical to thosein the first embodiment are designated by identical reference numerals,while omitting description thereof. FIG. 11 is a diagram showing anoperating screen displayed during execution of a program according tothe second embodiment, for looking up user information registered in theauthentication server 102 and/or editing contents of the userinformation. While in the first embodiment, as shown in FIG. 4, the SMTPauthentication user name and the SMTP authentication password are set asuser information, in the second embodiment, as shown in FIG. 11, theSMTP authentication user name and the SMTP authentication password arenot set.

In FIG. 11, entries in a column “User Name” 230 are registered as usernames in the authentication server 102. Entries in a column “Password”231 are passwords associated with the respective registered user names.Entries in a column “E-mail Address” 232 are E-mail addresses associatedwith the registered user names. An add key 240 is used for registering anew user. A delete key 241 is used for deleting a registered user. Aproperty key 242 is used for modifying registered contents. When theproperty 242 is depressed, the registered contents are displayed toallow modification thereof.

FIG. 12 is a flowchart of a log-in process executed by the MFP 100, foracquiring an E-mail address, a SMTP authentication user name, and a SMTPauthentication password. By executing this log-in process, the MFP 100requests the authentication server 102 to perform user authentication,whereby the E-mail service can be used using a designated user name.This also applies to the MFP 101, and therefore a description will begiven of the log-in process of the MFP 100 alone.

After the main power of the MFP 100 is turned on and initialization ofthe memory, I/O ports, etc. is executed, the present log-in process isstarted on condition that “User Authentication” is set to “Execute” bysystem user configuration. In this state, processing requiring useroperation, such as copying, is disabled, and a screen prompting the userto enter a user name is displayed on the operating section 133.

First, a user name entry screen is displayed, and entry of a user nameby the user is awaited (step S31). When the user name is entered, entryof a password is awaited (step S32). When the password is entered, theuser name and the password are sent to the authentication server 102 forauthentication thereby (step S33).

Then, it is determined whether or not “authentication OK” has beenreturned from the authentication server 102, i.e. whether or not it isconfirmed by the authentication that the entered user name and passwordmatch the user name 230 and the password 231 registered in theauthentication server 102 (step S34). If an invalid user name and/or aninvalid password have/has been entered, i.e., if not “authentication OK”but “authentication NG” has been returned, the process returns to thestep S31, wherein the same processing as described above is carried outagain on the user name entry screen. On the other hand, if“authentication OK” has been returned, an E-mail address 232 of the userhaving logged in, which is registered in the authentication server 102,is acquired from the authentication server 102 (step S35).

After acquisition of the E-mail address, a SMTP authentication user name306, among SMTP authentication user names set for each of users ofapparatuses such as the MFP 100 or the MFP 101, is acquired (step S36)Further, a SMTP authentication password 307 also set for each of theusers of the apparatuses is acquired (step S37), followed by terminatingthe present process.

When the user authentication is normally completed, the processingrequiring user operation, such as copying or transmission (SEND),becomes executable. Although in the present embodiment, the user nameand the password are entered for user authentication a method usingbiometrics authentication based on a fingerprint, an iris pattern, orthe like, or a method using a contact-type or non-contact-type controlcard may be employed.

FIG. 13 is a diagram showing a transmission setup screen displayed onthe operating section 133. On the transmission setup screen, which isused for a “Send” operation, assuming that a user logs in using a username “syain1”, the user name “syain1” used by the user for log-in isdisplayed at the upper left corner of the screen.

In a field “Reading size” 300, the size of an original to be read by thescanner 134 is designated. For originals to be read, any one of sheetsizes including A3, A4, A5, B4, B5, 11*17, LTR, and STMT, and theorientation of the sheet can be designated. In FIG. 13, “Auto” iscurrently set in the field “Reading size” 300, and hence a valuedetected by an original detection sensor incorporated in the scanner 134is read in.

In a field “Resolution” 301, a resolution in which an original is to beread by the scanner 134 can be designated. For the resolution, any oneof 200*100 dpi, 200*200 dpi, 200*400 dpi, 300*300 dpi, 400*400 dpi and600*600 dpi can be designated. In FIG. 13, a default value 200*200 dpiis currently set. Further, in a field “Details” 302, it is possible tospecify detailed operations for scanning, such as scanning density, thetype of the original, double-sided reading, page continuous printing,and image quality adjustment.

In a field “Subject” 304 is entered a title given to an E-mail to besent, and in a field “Body” 305 is entered the body of the E-mail. Wheneach of the setting fields is selected, a software keyboard is displayedto allow entry of a character string. A field “Address” 303 is providedfor specifying a destination address. The address is selected from theaddress book (see FIG. 8) in the first embodiment.

The SMTP authentication user name 306 and the SMTP authenticationpassword 307 are a user name and a password, respectively, which areused in transmitting E-mail data to the mail server 103, using the SMTPprotocol. The user name and password are set parameters stored in theapparatus used by the user, the set parameters being set on auser-by-user basis. When a user logs in, the SMTP authentication username 306 and the SMTP authentication password 307 are displayed as setparameters on the transmission setup screen. These set parameters can bechanged.

The image data read in by the scanner 134 is transmitted by thetransmission process in FIG. 9 according to the first embodiment. In theSMTP authentication process in the step S17 of the transmission process,authentication is performed using the SMTP authentication user name 306and the SMTP authentication password 307.

According to the second embodiment, the same advantageous effects asprovided by the first embodiment can be obtained. Further, a MFP, whichstores the SMTP authentication user name and the authenticationpassword, is allowed to request the mail server 103 to perform SMTPauthentication to thereby execute transmission of an E-mail or the like.

Although in the above-described embodiment, SMTP authentication isperformed by the mail server, this is not limitative, but if the SMTPserver and the POP server are implemented by the same apparatus, it ispossible to employ various other methods including a method in which auser name and a password for POP authentication according toPOP-before-SMTP are used.

The present invention is not limited to the above described embodiments,but can be modified in various manners within the scope of the presentinvention insofar as functions as recited in the appended claims or thefunctions performed by the construction of either of the above describedembodiments can be achieved.

For example, although in the first embodiment, the SMTP authenticationuser name and the SMTP authentication password are managed by theauthentication server, and by a MFP in the second embodiment, it may beconfigured such that the management can be switched between theauthentication server and the MFP. Further, although the authenticationserver is provided on the network to authenticate user information froma plurality of PCs and MFPs, the same advantageous effects as providedby the first and second embodiments can also be obtained byincorporating the function of the authentication server into the MFPs.

It is to be understood that the object of the present invention may alsobe accomplished by supplying a system or an apparatus with a storagemedium (or a recording medium) in which a program code of software,which realizes the functions of either of the above describedembodiments is stored, and causing a computer (or CPU or MPU) of thesystem or apparatus to read out and execute the program code stored inthe storage medium.

In this case, the program code itself read from the storage mediumrealizes the functions of either of the above described embodiments, andhence the program code and a storage medium on which the program code isstored constitute the present invention.

Further, it is to be understood that the functions of either of theabove described embodiments may be accomplished not only by executingthe program code read out by a computer, but also by causing an OS(operating system) or the like which operates on the computer to performa part or all of the actual operations based on instructions of theprogram code.

Further, it is to be understood that the functions of either of theabove described embodiments may be accomplished by writing the programcode read out from the storage medium into a memory provided in anexpansion board inserted into a computer or a memory provided in anexpansion unit connected to the computer and then causing a CPU or thelike provided in the expansion board or the expansion unit to perform apart or all of the actual operations based on instructions of theprogram code.

Further, the above program has only to realize the functions of eitherof the above-mentioned embodiments on a computer, and the form of theprogram may be an object code, a program executed by an interpreter, orscript data supplied to an OS.

Examples of the storage medium for supplying the program code include afloppy (registered trademark) disk, a hard disk, a magnetic-opticaldisk, a CD-ROM, a CD-R, a CD-RW, a DVD-ROM, a DVD-RAM, a DVD-RW, aDVD+RW, a magnetic tape, a nonvolatile memory card, and a ROM.Alternatively, the program is supplied by downloading from anothercomputer, a database, or the like, not shown, connected to the Internet,a commercial network, a local area network, or the like.

CROSS REFERENCE TO RELATED APPLICATION

This application claims priority from Japanese Patent Application No.2003-386985 filed Nov. 17, 2003, which is hereby incorporated byreference herein.

1. A communication apparatus connected to an authentication apparatusand a mail distributing apparatus via a network, for transmitting anelectronic mail via the mail distributing apparatus according to apredetermined transmission protocol, comprising: an input device viawhich user information is input; a user authentication requesting devicethat requests the authentication apparatus to authenticate the inputuser information; an authentication information acquisition device thatis operable when the user information is authenticated, to acquireinformation for authentication according to the transmission protocolassociated with the authenticated user information from theauthentication apparatus; a transmission authentication requestingdevice that requests the mail distributing apparatus to authenticate theacquired information for authentication, according to the transmissionprotocol; and a transmission device that is operable when the acquiredinformation for authentication is authenticated, to transmit anelectronic mail to the mail distributing apparatus according to thetransmission protocol.
 2. A communication apparatus as claimed in claim1, wherein the authentication apparatus comprises a storage device thatstores an electronic mail address associated with the user informationand the information for authentication according to the transmissionprotocol associated with the user information, and said authenticationinformation acquisition device acquires the electronic mail address andthe information for authentication stored in said storage device.
 3. Acommunication apparatus as claimed in claim 1, wherein the informationfor authentication comprises a user name and a password for SMTPauthentication, the user name and the password being associated with theuser information.
 4. A communication apparatus connected to a maildistributing apparatus via a network, for transmitting an electronicmail via the mail distributing apparatus according to a predeterminedtransmission protocol, comprising: an authentication information storagedevice that stores information for authentication according to thetransmission protocol; an input device via which user information isinput; a user authentication requesting device that requestsauthentication of the input user information; an authenticationinformation acquisition device that is operable when the userinformation is authenticated, to acquire information for authenticationaccording to the transmission protocol associated with the authenticateduser information from said authentication information storage device; atransmission authentication requesting device that requests the maildistributing apparatus to authenticate the acquired information forauthentication, according to the transmission protocol; and atransmission device that is operable when the acquired information forauthentication is authenticated, to transmit an electronic mail to themail distributing apparatus according to the transmission protocol.
 5. Acommunication apparatus as claimed in claim 4, wherein saidauthentication information storage device stores an electronic mailaddress associated with the user information and the information forauthentication according to the transmission protocol associated withthe user information, and said authentication information acquisitiondevice acquires the electronic mail address and the authenticationinformation stored in said authentication information storage device. 6.A communication apparatus as claimed in claim 4, wherein the informationfor authentication comprises a user name and a password for SMTPauthentication, the user name and the password being associated with theuser information.
 7. An electronic mail transmitting method executed bya communication apparatus connected to an authentication apparatus and amail distributing apparatus via a network, for transmitting anelectronic mail via the mail distributing apparatus according to apredetermined transmission protocol, comprising: an input step ofinputting user information; a user authentication requesting step ofrequesting the authentication apparatus to authenticate the input userinformation; an authentication information acquisition step of acquiringinformation for authentication according to the transmission protocolassociated with the authenticated user information from theauthentication apparatus, when the user information is authenticated; atransmission authentication requesting step of requesting the maildistributing apparatus to authenticate the acquired information forauthentication, according to the transmission protocol; and atransmission step of transmitting an electronic mail to the maildistributing apparatus according to the transmission protocol, when theacquired information for authentication is authenticated.
 8. Anelectronic mail transmitting method executed by a communicationapparatus connected to a mail distributing apparatus via a network, fortransmitting an electronic mail via the mail distributing apparatusaccording to a predetermined transmission protocol, comprising: an inputstep of inputting user information; a user authentication requestingstep of requesting authentication of the input user information; aretaining step of retaining information for authentication according tothe transmission protocol on a user-by-user basis; an authenticationinformation acquisition step of acquiring information for authenticationaccording to the transmission protocol associated with the authenticateduser information, from the authentication information retained in saidretaining step; a transmission authentication requesting step ofrequesting the mail distributing apparatus to authenticate the acquiredinformation for authentication, according to the transmission protocol;and a transmission step of transmitting an electronic mail to the maildistributing apparatus according to the transmission protocol, when theinformation for authentication is authenticated.
 9. An electronic mailtransmitting program executed by a communication apparatus connected toan authentication apparatus and a mail distributing apparatus via anetwork, for transmitting an electronic mail via the mail distributingapparatus according to a predetermined transmission protocol,comprising: an input module for inputting user information; a userauthentication requesting module for requesting the authenticationapparatus to authenticate the input user information; an authenticationinformation acquisition module for acquiring information forauthentication according to the transmission protocol associated withthe authenticated user information from the authentication apparatus,when the user information is authenticated; a transmissionauthentication requesting module for requesting the mail distributingapparatus to authenticate the acquired information for authentication,according to the transmission protocol; and a transmission module fortransmitting an electronic mail to the mail distributing apparatusaccording to the transmission protocol, when the acquired informationfor authentication is authenticated.
 10. An electronic mail transmittingprogram executed by a communication apparatus connected to a maildistributing apparatus via a network, for transmitting an electronicmail via the mail distributing apparatus according to a predeterminedtransmission protocol, comprising: an input module for inputting userinformation; a user authentication requesting module for requestingauthentication of the input user information; a retaining module forretaining information for authentication according to the transmissionprotocol on a user-by-user basis; an authentication informationacquisition module for acquiring information for authenticationaccording to the transmission protocol associated with the authenticateduser information, from the authentication information retained by saidretaining module; a transmission authentication requesting module forrequesting the mail distributing apparatus to authenticate the acquiredinformation for authentication, according to the transmission protocol;and a transmission module for transmitting an electronic mail to themail distributing apparatus according to the transmission protocol, whenthe information for authentication is authenticated.